The present invention relates to a semiconductor device using a TFT (thin film transistor), and to a process for fabricating the same. More particularly, the present invention relates to a semiconductor device usable for a liquid crystal display device of an active matrix type.
Semiconductor devices comprising TFTs include liquid crystal display devices of active matrix type and image sensors. When exposed to air, the TFTs for use in the devices enumerated above undergo degradation due to moisture, etc., of the air. This problem is overcome by covering the TFT with a passivation film of a material containing silicon nitride as the principal component thereof. However, in case aluminum is used for the source/drain electrodes and interconnections under the passivation film, hillocks tend to generate on the surface of the aluminum film due to the heat which generates at the deposition of a passivation film. Hillocks lead to a problem of short circuit.